DETECTION USING ANTISPERM MONOCLONAL-ANTIBODIES OF SHARED EPITOPES EXPRESSED BY HUMAN SPERMATOZOA AND OOCYTES

Objective: To determine whether human spermatozoa and oocytes share co mmon antigenic epitopes, supporting the hypothesis that their cross-li nking by antisperm antibodies present in the clinical sera of infertil e couples could promote sperm adhesion to the oolemma. Design: Human a nd hamster eggs were studied for the presence of antigens recognized b y a panel of World Health Organization Task Force monoclonal antibodie s (mAbs) originally raised against human spermatozoa. A new technique was devised, using frozen sections of paraformaldehyde-fixed individua l human and hamster eggs, to screen rapidly antisperm mAbs for egg rea ctivity. Living zona-free human and hamster eggs then were exposed to Covaspheres (Duke Scientific, Pale Alto, CA) coupled with these mAbs t o document the presence of reactive epitopes on the oolemma. Setting: Academic research environment. Main Outcome Measure(s): Indirect immun ofluorescence and Covasphere resetting.Result(s): Eleven of 37 antispe rm mAbs tested reacted with fixed hamster eggs and 10 reacted with hum an eggs. Five of 6 mAbs reactive with both fixed eggs also reacted wit h the oolemma of living, zona-free eggs. Conclusion(s): Common antigen ic epitopes, some of which are shared with somatic tissues, exist on t he oolemma of human eggs and on the plasma membrane of human spermatoz oa. (C) 1997 by American Society for Reproductive Medicine.